System of control.



R. E. HELLMUND, R. E. FERRIS 61 L. M. PERKINS.

SYSTEM OF CONTROL. APPLICATION FILED MAY 20. I916.

1,274,711. Patented Aug. 6, 1918.

arms? 17' /a WITNESSES INVENTORS. /9 Rudolf E. He/lmuna,

Ra l1 EYFrr/a, & Q Ground Lauc-gqce M. Perkins.

ATTORNEY UNITED STATES PATENT OFFICE.

aunoLr n. HELLMUND Ann RALPH a FEBRIS, or swrssvama'm TJAURENCE u,

rnnxms, or WILKINSBUBG, rnnnsuvmm, ASSIGN'OBS 'ro wns'rmanousn nmcrarcmn Mmumcroame comrm, n ,coaronarrou or rmmsnvnzu.

Specification of Letter: Patent.

SYSTEM OF CONTROL.

Patented Aug. o, 1918.

Application filed Kay 20, 1918. Serial No. 98,785.

vTo all whom it may concern.-

Be it known that we, RuoonrE. HELL- Mom), a subject of the Emperor of Germany, and a resident of Swissvale in the county of Allegllleny and State of l ennsyl- Vania, .R'ALPH F-ERRIS, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, and LAURENCE M. PERKINS, a citizen of the United States, and a resident of Wilkinsbur in the county of Allegheny and State of ennsylvania, have invented a new and-useful Improvement in Systems of ently embody certain advantages and novel features, as hereinafter more specifically se forth.

In the operation of regenerative control systems, one of the first considerations is'to protect the vehicle and the momentumdriven machines from injury, particularly with respect to over-speeding. Such conditions call, for a system of regeneration wherein a slight rise in the speed of the vehicle causesa relatively large increase in the regenerated current, that is, in the braking effort of the vehicle. However, a system having this characteristic is not very stable, since the regenerated current is'materially affected by the unavoidable fluctuations of supply-circuit voltage, which condition is liable to cause damage to the momen-.

tum-driven machines, such as over-heating, flash-over. troubles, etc.

the regenerated current is not very sensitive to suppl -circuit voltage-fluctuations, that is to say, oes not vary to any great extent in treme characteristics, whereby a relatively accordance with such. fluctuations or with slight changes of speed. The most practical system, therefore, appears to be a compromise between the above-mentioned ex- For this reason, it is desirable to employ a .system wherein small increase in regenerated current, as the vehicle speed increases, obtains.

The first system reclted above, wherein a relatively large increase of regenerated current 'is produced by a slight rise in vehicle speed, may be secured by exciting the mainma'chine field windings from an auxiliary. source of energy, such as a motor-generator set, battery, etc., the voltage of which rethe load thereof increases.

If, the auxiliary exciting voltage is caused to rise in a materially greater ratio than does the load, then the above-mentioned second system is obtained which is unduly vpreferably employed for main field-winding excitation purposes may be briefly stated as follows: First, the driving motor of the motor-generator set should be of the series type, whereby the speed of the auxiliary machines may vary in accordance with material vchanges of supply-circuit voltage and thus keep pace with'the desirable main fieldwinding excitation under varying condi- ,mains substantially constant or decreases as tions and also whereby the motor may be f relatively insusceptible to flash-over troubles, particularly upon the resumption of supply-circuit voltage after atemporary interruption thereof caused, for example,

by the vehicle current-collecting device leaving' the sup ly-circuit conductor As is wel -known, t e series-type motor is less liable to flash-over difliculties than theshunt type motor, since the field-winding flux of a series machine builds up relatively rapidly under the above-mentioned conditions of a sudden resumption of supply-circuit voltage, and thus the field flux is not unduly distorted by the initial restored armature current flux and; consequently, flashover conditions do not obtain. On the other hand, a shunt-excited machine roduces the familiar damping or choke-ooi effect in the field circuit, which leads to an undesirable predominance of restored armae ture-current flux over the simultaneous shunt-field-winding flux, with the consequent liability to flash-over difficulties.

Secondly, it is obvious that, even though the driving motor of the motor-generator set is preferably series-excited, means should be provided for preventing the motor from running away, that is, over-speeding, without employing a shunt field winding which entails the above-mentioned undesirable tendency to flash-over conditions.

4 Thirdly, the necessary regulation of the system to compensate for the gradual decrease of vehicle speed should preferably in- .volve the handling of relatively small auxiliary currents rather than the main regene erated current, whereby the initial cost and operatingcharges' of the system are materially reduced. It is our aim," in the hereinrelia after-described systems, to accomplish the above-mentioned results in as simple and inexpensive a manner as is compatible with 1e operation.

Surinvention may best be understood-by reference to the accompanying drawing, wherein Figure 1 is a diagrammatic view'of a system of control embodying our invention; and Fig. 2 and Fig. 3 are similar diagrammatic views of modified systems constructed and arranged in accordance with the invention.

Referring to Fig. '1," the system here shown comprises a plurality of supply-circuit conductors respectively marked Trolley and v windings A and A and field-magnet windings F} and F of the series type; a plurality of mam-circuit resistors R and R that are associated with the respective main armatures in a manner to be described; and an auxiliary motorgenerator set having its driving armature winding M fed from the supply circuit and its generator or exciting armature winding G connected to excite the main field windings F and F The armaturewindings M and Gmay be mechanically-connected in any suitable man'- ner, as by a shaft 8. The driving armature,

Winding M is provided with a series-connected field-magnet windingIi ll and a second field-magnet winding MB of the series type that is energized in accordance with the regenerated current; while the exciting armature winding G is provided with a supply-circuit-excited or shunt field-magnet winding Gil and a second field-magnet winding GF of the series type that is connected in series relation with the field-magnet winding MF to be energized in accordance with the regenerated current.

M; As indicated-by the' positive signs and the 'arriiws', the two field-magnet windings for the driv ng armature M are adapted to act cumulatively to assist the voltage 0 Groundl; a plurality of main dynamo-elec-H tr1c machines respectively having armature tive control system that is employed is not essential to our present invention, we have not deemed it necessary to describe, in detail, means for efiectingthe illustrated circuit connections or for inaugurating regenerative operation. The main-circuit connections about to be described are fully set forth and claimed in a copending application of R. E. Hellmundyserial No. 44,443, filed August 9, 1915, and assigned to the Westinghouse Electric & Manufacturing Company. a 1

Assuming that regenerative operation has been started and that the various circuit connections are as shown in Fig. 1, such connections may be traced as follows: One main circuit is completed from the trolley through junction-point 10, conductor 11, main armature A junction-point 12,. main-circuit resistor R a switching device 13, here conventionally shown as an arrow-head, junction-point 14, ,con' uctors 15 and 16, fieldmagnet winding Gr for the exciting armature G, conductor 17, field-magnet 'winding MB for the driving armature winding M and conductors 18 and 19 to the negative conductor round. 7

A secon similar main circuit is completed from the junction-point 10 through conductors 20 and 21, main' armature A junction-point 22, main-circuit resistor R 3, switching device 23 that corresponds to the pther switching device 13, and thence through the junction-point 14, as just recited.

One terminal 24 of the exciting armature Winding G is connected through conductor 25 to the conductor 15 and junction-point :14, wherethe circuit divides, one branch ineluding switching device 13, main-circuit resistor R junction-point 12, main field winding F and conductor 26 to another junction-point 27, and theother branch including switching device 23, main-circuit resistor R junction-point 22, main field winding F and the junction-point 27, whence circuit is completed through conductor 28 to the other terminal 29 ofthe exciting armature winding Gr.-

n auxiliary circuit is completed from :the conductor 20, through oonductors'30 and 31, driving armature winding M of the mo-* tor-generator set,series field winding MI 130" for the armature winding M and conductors 32 and 19 to the negative conductor ground. A further auxiliar circuit is completed from" onductor 30 t rough conductor 33, auxiliary resistor AR, conductor 34, shunt field winding GrF for the exciting armature winding G and conductor 35 to the negative conductor 19. A second auxiliary reslstor AR 'is connected, in parallel relation, to the shunt field winding GF and is adapted'to be varied in active circuit value by means of a plurality of suitable switches 1, 2, a and 4.

The operat1onof the above-described system, in so far as it pertains to our present invention, may be'setforth as follows: upon an incipient increase of regenerative current in the main momentt un driven 'armature A, for example, a. correspondingly augmented woltage drop occursacross "themamclrcuit res1storR- whereby afiaccordmgly reduced voltage is available for deliveryito the main field winding F from the approxi T:-

mately constant-voltage -exciting armature winding G. Such reduction of main field- 1 Obviously, anincipient decrease of regenerated current in-felther mam armature w1ll effect a corresponding increase of current in the allied main field winding and thus maintainthe desired conditions,

However, a further inherent regulating action occurs in the motor-generator set to aid in accomplishing'the desired object. In the case of the above mentloneo. inciplent 1ncrease of regenerated current, 9 corresponding increase of the current traversing the fieldmagnet windin GF obtains, and, by reason of the differential relation of the field-magnet windings GF and GF, the resultant or effective flux in the armature winding' G is accordingly reduced and thus, again, a decreased current is delivered to the main field winding F The'two' above-mentioned regulating actions, of course, occur at a relatively rapid rate and thus the variations of the regenerated current may be maintained within desirably narrow lim ts.

Moreover, although no shunt field winding for the driving armature winding M is provided under light-load conditions of the auxiliary machines, which entails a relatively small exciting current in the series field winding MF a sutlicient current flows through the other field winding MF at all times to insure a flux in the driving armature winding M of sufficient strength to prevent the armature from over speeding. Thus, the desired result is attained without re uiring the use of a shunt-field winding.

0 regulate the system inorder to comincrease 1:

pensate for the gradual decrease of speed of the momentumalriven machines, the switching devices 13 and 23 ma be actuated, preferably in accordance with the regenerated current, as fully described in the above mentioned co-pending application of R. E. Helllnund, although such undesira. ble and relatively expensive main-circuit regulation may be dispensed with by suit-*- ab e design of parts inour present inven- 'tion. For example, the effective excitation ofthe shunt field winding GF -for the exciting armature winding G maybe gradually increased by successively opening the switches 1 to 4, inclusive, as the vehicle speed decreases, or the other auxiliary res stor AR may be gradually excluded, from circuit to perform a similar function of efi'ect ing a gradual increase of' the main fieldwinding excitation. The two last-recited methods involve the use of relatively small switching devices and the handling of slight currents and, consequently, are advantageous inthese respects.

Reference may now be had to Fig. 2,

wherein the only difference from the system that has just been described resides in the substitution of. a shunt field winding- GrF for the supply-circuit-excited field-magnet winding GF of the previous system. The field winding GF is connected in parallel relation to a-translating device TD, such as a resistor, that is connected in series relation .with the driving armature winding M. As indicated by thecorresponding arrow, the

current in theshunt field winding GF? is adapted to assist the voltage of the exciting armature winding G, while the other fieldmagnet winding GF is again connected dif-v ferentially, that is, to oppose the action of the shunt-field winding GF The general inherent regulating operation of the present system is obviously substantiallylike that set forth in connection with 1, and no other exposition thereof is believed to be necessary here. However, a somewhat different method of compensating for the gradual decrease in speed of the momentum-driven machines is employed, such method embodying the use of a plurality of suitable switches 5, 6 and 7 that are respecefi'ects. a gradual, increase of the current traversing1 the shunt field winding GrF to e voltage of the exciting armature winding G in the desired ratio for accom- 1 plishing the intendedfunctions, as will be understood.

Referring now to Fig. 3, the main-circuit connections and the arrangement of armature and field windings of the driving motor of the motor-generator set are like those employed in the system that is illustrated in 130.

Fig. 1. However, the terminal 24 of the exciting armature winding G is connected through conductor 25 to a junction-point or lower-terminal point 45 of a field-magnet winding GF, whence circuit is completed through conductor 15, as previously described. Consequently, the field winding GF carries the regenerated or main-arma-' driving armature winding M and conductors 18 and 19 to the negative conductor ground Another auxiliary resistor Alt is connected in shunt relation to the supply-circuit-excited field-magnet winding G1 and is i adapted to be varied in active circuit value by means of a plurality of suitable switches '1,2and3.,

In the present instance, the field winding GF is connected to assist the voltage of the so exciting armature winding G, while the shunt field winding GF is adapted to oppose such voltage, that is to ay, the field windings GF and GB are di erentially related, as indicated by the positive and nega- 85 tive signs and the corresponding arrows, but in the reverse-manner from that employed in the system of Fig. l. a

However, the inherent regulating action of the two field windings for the exciting armature winding G follows similar principles to those set forth in connection with the previous systems. Briefly, anincipient increase in the regenerated or main armature current correspondingly augments the current traversing the field-magnet .winding GF, and the design of parts is such that the resultant or effective field flux that is produced by the two difierentially-related' field windings is accordingly reduced and the desired decrease of main field-winding excitation obtains. Although such reduction of main field-winding current also influences the voltage of the driving armature winding M, it will be appreciated that this fact may be taken into account in designing the moversed arrangement'of the shunt-excited and i t6 series-excited field windings for the armature winding G, that is to say, by gradually closing the switches 1, 2 and 3 to thus correspondingly decrease the diiferential efi'ect .of the supply-circuit-excited field-magnet winding GrF and permit of the desired in.- crease of main field-winding excitation during the gradual decrease of vehicle speed.

We do not wish to be restricted to the specific circuit connections or arrangement and location of parts, particularly the auxiliary 76 v regulating arrangements, ,hereinbefore set forth, as various modifications thereof may beefiected without departing from. the spirit and scope of our invention.- We desire,

therefore, that only such limitations shall be 80 imposed as are indicated in the appended claims. I

We claim as our invention:

' 1. In a system of control, the combination with asupply-circuit and a main dynamo- 86 electric machine having an armature and a field winding, of a plurality of auxiliary mechanically-connected armature windings respectively driven from said supply circuit and connected to excite said field winding, a 90 plurality of differentially-related field-magnet windings for the exciting armature winding, and a plurality of cumulativelyrela-tedfield-magnet windings for the driving armature winding.

2. In a system of control, the combination with a supply-circuit and a main dynamoelectric machine having an armature and a field winding, of a plurality of auxiliary mechanically connected armature windings one of which is adapted to excite said field winding "and the other for driving purposes, anda plurality of field-ma etwindings of the series type for the driving auxiliary armature winding energized by difi'erent cur- 106 rents and mutually functioning to prevent over-speed conditions of said driving armature winding.

3. In a system of control, the combination with a supply-circuit and a main dynamo- 110 electric machine havin an armature and a field winding, of a plurality of auxiliary mechanically-connected armature windings respectively adapted for-driving purposes and to excite said field winding, and a plu- 5 rality of field-magnet windings of the series type for the driving auxiliary armature winding respectively energized by' the mainarmature current and the driving armature current.

4. In a system of control, the combination With-a supply-circuit and a main dynamoelectric machine havin an armature and a field winding, of a p urality of auxiliary mechanically-connected armature windings respectively adapted for driving purposes an to excite said field winding, a plurality of field-magnet windings for the respective auxiliary armature windings energized in accordance with themaini-armature-current,

a series field-magnet winding for the drivin armature winding, and a shunt-excited fiel magnet winding for the exciting armature winding,

5. In a system of control, the combination of field-magnet windings for t e respective "auxiliary armature windings energized in accordance with the main-armature current,

. ing adapted to oppose its allied field" i armature windin s, a series field-ma respectively driven from'the su ture current and the total main-machine a series field-magnet winding for the driving armature windin adapted to aid its allied field winding an a shunt-excited-field-magnet winding for the exciting armature windwinding.

' 6. In a system of control, the combination I with a supply-circuit and a main dynamoelectric machine having an armature and a field winding, of a plurality of auxiliary mechanically-connected armature windings respectively driven from the supply circuit and connected to excite said field winding,

a plurality of field-magnet windings for the respective auxiliary armature windings energized 1n accordance with the main-armature current and adapted to respectively assist and oppose the voltage of the auxiliary et winding for the riving armature win ing adapted to aid its allied field winding, and

a supply-circuit-excited field-magnet winding for the exciting. armature winding adapted to oppose its allied field winding.

7. In a system of control, the combination with a supply-circuit and a main dynamoelectric machine havin an armature and a field winding, of a p urality of auxiliary mechanically-connected armature windings respectively driven from the su ply circuit and connected to excite said fie d winding, and a plurality of field-magnet windings for the respective auxiliary armature windings energized in accordance with the main-armature current and the total main-machine current, respectively.

8. In a system of control, the combination with a supply-circuit and a main dynamoelectric machine having an armature and a field winding, of a p urality of auxlliary mechanically-connected armature windings (ply circuit and connected toexcite said fie winding,

a plurality of field-magnet windings for the respective auxiliary armature windings energized in accordance w1th the main-armacurrent, respectively, a second field-ma et windin for the driving armature win ing adapte to assist its allied field winding W and a second field-magnet winding for the plurality of field-magnet windings for theres ective auxiliary armature windings energized in accordance with the main-armature current and the total main-machine current, respectively, a series field-ma et ,winding for the driving armature winding adapted to assist its allied field winding, and a supply-circuit excited field-magnet winding for the exciting armature winding adaptedto oppose its allied field winding. 10'. In a system ofeontrol, thecombination with a supply-circuit and a main dynamo-electric machine having an armature and a field winding, of a mechanically-connects armature windings respectively driven from said supply' circuit and connected to excite said field winding, a

plurality of difi'erentially-related field-mag-..

net windings for the exciting armature winding, and a plurality of cumulativelyrelated'fie-ld-magnet windings for the driv- (plurality of auxiliary ing armature winding, and means for regulati'ng certain of the auxiliary field windings to secure predetermined excitation of the main field winding.

11. In a system of control, the combination with a supply-circuit and a main dynamo-electric machine having an armature and a a field winding, of a plurality of auxiliary mechanically-connected armature windings respectively adapted for driving purposes and toexclte said field windin a plurality of field-magnet windings for t e respective auxiliary armature windings energized in accordance with the main-armature current, a series field-magnet winding for the drivin armature winding and .a shunt-excited fiel magnet winding i r the exciting armature winding, and means for varying the efiect of the shunt-excited field winding to maintain a substantially constant main-armature current,

12. In a system of control, the combination with a supply-circuit and a main dynamo-electric machine havingan armature and a field winding, of a plurality of auxiliary mechanically-connected armature windings respectively driven from the supply circuit and connected, to excite said field winding, a pluralityvof field-magnet windingsv for the adapted tov did its allied field winding, and a, su ply-circuit-excited field-ma et Winding or the exciting armature win ing adapted to oppose its allied field windings and means 101' varyin the efi'eot of the supplycircuit-excited fie d-Winding to maintain a substantially constant mam-armature cur rent.

13. In a system of control, the combination with e-sn p ly circuit and a main dynamo-electrio mac ine having an armature and a field winding, of an auxiliary motor-gencrater for exclting said field winding and hefiving ef plurality of field windings respee tively energized in eccordence with the mein :inachine load and with the motor-generator end:

14. in e system of control, the combinei em' 'ni mo-electric machine having an armature and e field winding, of e lurelity of auxiliary mechanically-connect armeture windings respectively and to excite said field winding and a plu relity of field windings for the driving auxiliery armature winding respectively energized in accordance with the main machine load and with the driving-auxiliary-armature load. Y

In testimony whereof, we have hereunto subscribed our names this 29th day of April,

RUDOLF E. HELLMUND. RALPH E, nnnnis. LAURENCE PERKINS.

adapted for driving purposes 

